#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;

int main() {
	string str;
	int sum = 0;
	cin >> str;

	int len = str.length();

	for (int i = 0; i < len; i++) {
		if (str[i] >= '1' && str[i] <= '9') {
			sum += (str[i] - '0');
		}
	}
	cout << sum << endl;
	return 0;
}